Hinge for a front bonnet of a motor vehicle

Abstract

A hinge for a front bonnet of a motor vehicle; the hinge is provided with a mobile bracket, which is rigidly connected to the front bonnet, and a fixed bracket, which presents an elongated shape, is hinged to the mobile bracket at a rotation axis of the hinge, and is rigidly connected to a frame of the motor vehicle by means of two fastening screws arranged through two through holes; the rotation axis is arranged at a first end of the fixed bracket, a first through hole presents an elongated shape and is arranged at a second end of the fixed bracket, and a second through hole presents a circular shape and is arranged in an intermediate position between the two ends of the fixed bracket; the first hole is engaged by a first fastening screw which is tightened to the frame with calibrated and limited tightening torque so as to allow a rotation of the fixed bracket about a second fastening screw in case of a collision against the front bonnet at the hinge.

1 ) A hinge ( 3 ) for a front bonnet ( 1 ) of a motor vehicle; the hinge ( 3 ) comprising:
 a mobile bracket ( 4 ), which is rigidly connected to the front bonnet ( 1 ); and   a fixed bracket ( 5 ), which presents an elongated shape, is hinged to the mobile bracket ( 4 ) at a rotation axis ( 6 ) of the hinge ( 3 ), and is rigidly connected to a frame ( 2 ) of the motor vehicle by means of two fastening screws ( 7 ,  8 ) which are arranged through two through holes ( 9 ,  10 ) obtained through the fixed bracket ( 5 ) itself; the rotation axis ( 6 ) is arranged at a first end of fixed bracket ( 5 ), a first through hole ( 9 ) is arranged at a second end of the fixed bracket ( 5 ) opposite to the first end, and a second through hole ( 10 ) is arranged in an intermediate position between the two ends of the fixed bracket ( 5 );   wherein, the first through hole ( 9 ) presents an elongated shape and is engaged by a first fastening screw ( 7 );   the second through hole ( 10 ) presents a circular shape and is engaged by a second fastening screw ( 8 ); and   the first fastening screw ( 7 ) is tightened to the frame ( 2 ) of the motor vehicle with a calibrated and limited tightening torque so as to allow a rotation of the fixed bracket ( 5 ) about the second fastening screw ( 8 ) in case of a collision against the front bonnet ( 1 ) at the hinge ( 3 ) and to consequently determine a lowering of the position of the rotation axis ( 6 ).   
     
     
         2 ) The hinge ( 3 ) according to  claim 1 , wherein the second fastening screw ( 8 ) is also tightened to the frame ( 2 ) of the motor vehicle with a calibrated and limited tightening torque so as to allow a rotation of the fixed bracket ( 5 ) about the second fastening screw ( 8 ) in case of a collision against the front bonnet ( 1 ) at the hinge ( 3 ) and to consequently determine a lowering of the position of the rotation axis ( 6 ). 
     
     
         3 ) The hinge according to  claim 1 , wherein the fixed bracket ( 3 ) comprises two reinforcement ribs ( 12 ), which are arranged at opposite side edges of the fixed bracket  5  itself. 
     
     
         4 ) The hinge ( 3 ) according to  claim 1 , wherein the fixed bracket ( 5 ) comprises a weakened area ( 13 ), which is arranged between the second through hole ( 10 ) and the rotation axis ( 6 ) and is adapted to collapse to consequently determine a further lowering of the position of the rotation axis ( 6 ). 
     
     
         5 ) The hinge ( 3 ) according to  claim 4 , wherein the weakened area ( 13 ) comprises a third weakening through hole ( 14 ) obtained through the fixed bracket ( 5 ). 
     
     
         6 ) The hinge ( 3 ) according to  claim 5 , wherein the third weakening through hole ( 14 ) presents an elongated shape arranged parallelly to the fixed bracket ( 5 ). 
     
     
         7 ) The hinge ( 3 ) according to  claim 6 , wherein the transversal dimension of the third weakening hole ( 14 ) is smaller than the transversal dimension of the portions of the fixed bracket ( 5 ) arranged about the third through hole ( 14 ) and on opposite sides of the through hole ( 14 ) itself.